I really like sloths, but one of their recently discovered habits might make me like them a little bit less…

As recently reported by Eckhard Heymann and colleagues, Linnaeus’s two-toed sloths Choloepus didactylus at the Estación Biológica Quebrada Blanco in north-eastern Peru have developed the delightful habit of climbing into an outdoor latrine building, seeking out the latrine contents AND EATING THEM (Heymann et al. 2010).

The behaviour was first reported in November 2001 when a sloth was discovered hanging from the wooden bars within the latrine. “It was scooping with one hand from the semi-liquid manure composed of faeces, urine and toilet paper and then eating from the hand” (Heymann et al. 2010, p. 1 of preprint). This wasn’t a one-off. More than 25 additional reports of sloths visiting and feeding in the latrine were made, and in fact the behaviour only stopped in 2007 when wire mesh was erected around the building. Good photos were taken, and two are reproduced here. The photo below shows a mother and baby emerging from the latrine [from Heymann et al. (2010); photos by M. Stojan-Dolar].

Why would a sloth want to climb into a latrine and eat human, errr, waste material? Heymann et al. (2010) make a few suggestions. Were the sloths interested in the faeces for nutritional reasons? Were they drinking the urine because they required the salt? Or were they interested in the insect larvae that were present? We don’t know: at the moment the reason for this behaviour is totally enigmatic. Indeed it’s possible that this behaviour will turn out to be widespread. After all, sloths live close to people in many places. Heymann et al. (2010) further speculate that sloths could act as vectors of human diseases and parasites as a result of these latrine visits.

Depending on your perspective, sloths might just have become even more interesting than they already are…. or, they might have become a lot less cute, and a lot more disgusting. Having thought about it, I’m actually not that bothered, and I still think sloths are neat and fascinating. But I think I might avoid touching them, cuddling them, or sniffing them from now on.

While a tad gross, this does add to our very sparse knowledge of the diet in Choloepus. Also seems to match the general assessment that two-toed sloths will eat pretty much anything. Looking forward to adding this tidbit to my latest papers!

Nature never ceases to surprise me. In a way, I’m glad that sloths aren’t as cuddly as so many make them out to be. It’s like when bonobos were discovered eating vertebrate meat: it broke another naive stereotype we had about animals, and showed a fascinating (though maybe a bit disarming) method of survival.

I remember having to use the “out house” in the country when I was younger and the big fear back then was spiders, snakes or a skunk. I thinking opening the door and seeing THAT coming up through it might scar a child for life.

Completely unrelated question: Aside from also being sloths, how do extinct ground sloths relate to modern sloths? That is, did ground sloths come out of the trees, or did tree sloths get up off the ground? Do modern sloths have a good fossil record? Is one group ancestral to the other in some way? Did ground sloths ALSO frequent ancient man’s prehistoric latrines?

How on earth could this be beneficial to them in any way?!?! Even if they are getting salt from the urine, or insects, the sheer amount of bad shit in there (excuse the pun) must far exceed whatever use they get out of it.

Well, I suppose in a little while we will see if this behavior gets ‘selected out’ or not

Zach: The two living sloth genera (Choloepus and Bradypus) have no fossil record, but there are tons of fossils of other sloths, which are probably all dubbed “ground sloths”. However, many of the smaller ones, like those in the Caribbean, probably did climb trees. I would guess that terrestriality is most likely primitive within Folivora.

A friend of mine in high school once found a dead horse. As he approached it, a possum crawled out of the decaying cadaver and slowly made its way off. That was the grossest story I ever heard, until now.

I never thought sloths were particularly fascinating. They are kind of cool looking, but aren’t most mammals? Anyway… this is really disturbing. I don’t know the sloth’s typical habitat and can only hope that it’s not near where I go camping.

I can’t imagine this is a good thing for them. I’d love to know if they have immunity to the bulk of what’s found living in these pits.

Perhaps unlikely, but maybe the habit of hanging from something (the seat) causes a powerful feeding reaction. Sea otters only eat while backfloating, they avoid eating while in a vertebrate-normal upright posture, even tasty food.

Do folivorous sloths have diminished taste buds or olfaction? Folivorous-herbivorous Gorillas eat their own feces, maybe post-intestinal microbiotic processed organics emit a scent paralleling the scent of cheese to people, an aquired aroma. After all, consumption of decomposed milk wouldn’t be expected for a descendant of supposed frugivores.

I know sloths are eaten by Harpy Eagles and other predators, but could this habit make them repulsive to some carnivores, either because of the smell and taste it gives their flesh or because of diseases carried?

Nothing wrong with eating faeces. I have a shortened colon and so don’t extract all of the nutriment from food on its first passage. For the second passage, I enjoy spreading it on toast with a lot of butter.

This is perhaps the only time in my life I’ve felt glad that ground sloths are extinct. Imagine seeing one of those rise up out of your outhouse. Without modern glyptodonts, I assume they would look for food wherever they could find it.

@ 26 and way OT:
Here in Korea one culinary specialty (which I will not try) is “ddong-duedji” (lit. shit-pig): pork from pigs that have been fed only human feces for their entire “lives”. (one way of recycling efficiently i guess…)

Sloths otherwise eat nothing but leaves…maybe they needed some nitrogen/protein from carnivore dung? Perhaps Megatherium really did swoop down on sabertooth kills!

(A phylogenetic argument for needing extra protein might be that other xenarthrans all eat much higher protein foods, perhaps the ancestral state for xenarthra, and sloths aren’t as good at pure herbivory as say ungulates?)

That second picture, isn’t that a three toed sloth? Are both types of sloths guilty of this odd behavior? Always knew Xenarthrans were a fascinating and mysterious bunch, but this “peculiar” incident opens up a whole new chapter of questions about them. Does anyone know if any similar behaviors have been recorded elsewhere outside Peru? I live in a country were sloths are common, but I never heard of anything like this. On the other hand, sloths are suspiciously absent from the local wildlife menu. Perhaps the native cultures just knew better…

An awful lot of mammalian feces consists of bacteria (usually at least 25%), as well as lost lining cells and some non-reclaimed breakdown products such as those that produce the characteristic color, so there would be nutrition available. If there wasn’t, we’d be up to our butts in unrecycled wastes.

And if the sloths aren’t at all compatible with the active little buggers they’re ingesting, disease wouldn’t be an issue.

First off, I’m surprised that the sloths not only eat fecal matter, but figured out that it collects in a latrine. Was there any information about whether this latrine was a simple open-air seat, or a Port-o-Potty design? If it’s the second one, that’d be unusually clever for a sloth.

Second, I’d forsee the sloths having more problems with the toilet paper than the waste material itself. Who knows what effects that soothing aloe could have on a sloth’s digestive tract…

March 17, 2008:
Derek came up with a great idea. There are these two-leg walking devils, and especially those of them who cannot stop watching us every minute of our lives – let’s just drive them crazy! We’ll think of something to do, something completely unreasonable and stupid, out-of-the ordinary that leave them toitally at loss for the rest of their whole miserabée lives… So, let’s rev up these grey cells…

Feb 12, 2010:
Jarvis – what a uick thinker that guy is!!! – has THE idea!

One study (Pirlot, 1980) suggests that the three-toed sloth Bradypus has relatively smaller olfactory bulbs than an armadillo. On the other hand, the hero of Darren’s post, the two-toed sloth Choloepus, has an olfactory organ that is fairly large – or at least not obviously smaller – than in other similarly-sized mammals (Adam, 1999; Yours truly, personal observation). I’d wager that by mammalian standards, the (two-toed) sloths’ sense of smell is neither particularly keen nor particularly poor. But we need more quantitative data to settle that question.

References:

Adam, P.J. 1999. Choloepus didactylus. Mammalian Species 621, 1-8.

Pirlot, P. 1980. Quantitative composition and histological features of the brain in two South American edentates. Journal für Hirnforschung 21, 1-9.

Sonntag, C.F. 1923. The comparative anatomy of the tongues of the Mammalia. IX. Edentata, Dermoptera, and Insectivora. Proceedings of the Zoological Society of London (34), 515-529.

Dartian, thanks, interesting. I was thinking, that since folivorous proboscis monkeys can eat leaves and ‘green’ fruits but never ripe fruits (which produce bloating), that perhaps a sloth could be somehow attracted to and be unaffected by pre-processed ripe fruits in feces (assuming that humans (and monkeys?) in tropical rainforests consume much fruit). Also there might be a parallel in armadillos having insensitivity/immunity to formic acid of fire ants, and sloths having insensitivity/immunity to plant leaf alkaloids. Armadillos are attracted to corpses, to get at the decomposer larval insects, but I don’t think sloth toilet-feasting is related to any attracted insects. A tangent: sloths and sea cows are unique in having abnormal vertebral counts, could algae-coated tree sloths (which are good swimmers) have derived from a miocene equatorial flood-forest variant of the “marine” sloth of Peruvian desert shores? I think the marine sloth evolved dense armadillo-like skin (manatees & alligators have very dense skin) and sunbathed on desert beaches between feedings on seagrass (like marine iguanas), using its claws both for burrows and clutching/raking seagrass. See: http://catalogue-of-organisms.blogspot.com/2008/04/swimming-sloth.html

could algae-coated tree sloths (which are good swimmers) have derived from a miocene equatorial flood-forest variant of the “marine” sloth of Peruvian desert shores?

Highly unlikely, because the marine sloths were a sideline, and because the tree sloths aren’t each other’s closest relatives: one of them is the sister-group to all other known sloths or something, the other is a megalonychid.

A tangent: sloths and sea cows are unique in having abnormal vertebral counts, could algae-coated tree sloths (which are good swimmers) have derived from a miocene equatorial flood-forest variant of the “marine” sloth of Peruvian desert shores?

By ‘abnormal vertebral counts’ I presume you mean their number of neck vertebrae? The basic – and, I suspect, insurmountable – problem with postulating similar ecological selection pressure (i.e., aquatic living, if I understood correctly what you were getting at) as the explanation for sloth and sirenian cervical vertebrae count is that their respective neck vertebrae numbers are unusual in different ways:

-Strictly speaking, ‘sea cows’, i.e., dugongs Dugong dugon, are not unusual regarding their neck vertebrae counts; dugongs have the standard mammalian seven. Manatees Trichechus, on the other hand, have a reduced number of cervical vertebrae: they have only six (Buchholtz et al., 2007).

-Among extant sloths, three-toed sloths Bradypus have a greater number of cervical vertebrae than usual for mammals: they have eight to ten, with nine being the typical number. Two-toed sloths, on the other hand, have fewer cervical vertebrae than usual for mammals, but there is variation even among Choloepus species in this regard. The common two-toed sloth C. didactylus usually has seven neck vertebrae, like most mammals, but in Hoffmann’s two-toed sloth C. hoffmanni neck vertebrae count varies from five to seven, with six being the typical number (Buchholtz & Stepien, 2009).

In short, there is no discernible pattern, or at least no ecologically correlated pattern, in the variation in neck vertebrae count in these mammalian taxa: the aquatic manatees and the arboreal Hoffmann’s sloth have fewer cervical vertebrae than mammals typically; the aquatic dugong and the arboreal common two-toed sloth have the typical mammalian cervical vertebrae count; and the arboreal three-toed sloths have more cervical vertebrae than mammals typically.